A microwave notch filter is a key component in RF signal processing. This filter is used to remove unwanted signals from the RF spectrum, ideally without disturbing the desired signals. Key characteristics desired from such a filter are high resolution (narrow attenuation response), high extinction (high peak attenuation), and high bandwidth (large tunability of the notch frequency).
Existing filters suffer from severe drifts that prevent the creation of a stable high extinction filter. This poor long term stability in turn limits the applicability of the existing filters.
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